This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-171599, filed Jun. 6, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
This invention relates to an electronic apparatus, such as a mobile phone, PDA (Personal Digital Assistant), or an electronic organizer, and more particularly to a folding electronic apparatus.
2. Description of the Related Art
A folding mobile phone is such that, for example, a first unit provided with a speaker, a display unit, and others is connected with a second unit provided with a microphone, a keypad, and others via a hinge unit in such a manner that they can rotate. This type of mobile phone is folded up small in the standby state in such a manner that the first and second units are laid on top of the other, thereby providing a good portability. On the other hand, when starting to communicate, the user unfolds the first and second units, thereby securing a high operability and a good visibility.
In this type of mobile phone, a flexible substrate is used to electrically connect the circuit provided in the first unit to the circuit provided in the second unit.
FIG. 5 shows the configuration of a mobile phone written in Jpn. Pat. Appln. KOKOKU Publication No. 2821333. In this mobile phone, the front case 1-1 of the first unit 1, the front case 2-1 of the second unit 2, the rear cover 1-2 of the first unit 1, the rear cover 2-2 of the second unit are provided with arc-like curved surface parts 1-3, 1-4, 2-3, 2-4, respectively. These curved surface parts 1-3, 1-4 and 2-3, 2-4 are jointed with one another, thereby constituting a cylindrical axis member. This axis member makes a hinge 3. The circuit in the first unit 1 is connected to the circuit in the second unit 2 by a flexible substrate 4. The flexible substrate 4 is in the form of a belt. The flexible substrate 4 is rolled spirally once in the cylinder of the hinge 3 along its inside diameter, with both ends of the substrate 4 pulled into the inside of the first and second units 1 and 2. At both ends of the flexible substrate 4, connectors are provided. The connectors are connected to the circuits in the first and second units 1 and 2. With this configuration, the tension exerted on the flexible substrate 4 or the slack exerted on the substrate 4 at the time of opening and closing the units 1 and 2 can be absorbed inside the hinge 3.
With such a conventional configuration, however, the flexible substrate 4 is rolled spirally. Accordingly, the flexible substrate 4 rubs against itself complicatedly, with the result that the flexible substrate 4 tends to deteriorate. Above all, it is impossible to avoid the rubbing of both the side edges of the flexible substrate 4 against one another. As a result, there is a danger that the wiring patterns near both the edges of the substrate 4 will come off or break.
In recent years, double-sided flexible substrates which have wiring patterns formed on both sides of a single substrate and multilayer flexible substrates formed by laying a plurality of substrates one on top of another have been widely used. This type of flexible substrate, however, generally has a poor flexibility. Therefore, if these flexible substrates were used in folding mobile phones, the substrates would be more liable to deteriorate, resulting in a decrease in the reliability of the mobile phones.
The object of the present invention is to provide not only a folding electronic apparatus which decreases the deterioration of its flexible substrate and thereby improves the reliability of the apparatus but also the flexible substrate.
According to an aspect of the present invention, a crank-shaped flexible substrate is used. The flexible substrate is composed of a first belt-like part, a second belt-like part, and a middle part which connects the first and second belt-like parts so as to form a crank shape. At least one of the first belt-like part and the second belt-like part is rolled with the middle part as an axis to form a roll buffer part. The roll buffer part is housed in a cylindrical axis member of a hinge unit. In this state, a tips of the first and second belt-like parts are pulled into the first and second units through an opening made in the side face of the cylindrical axis member. Then, the tips of the pulled-in first and second belt-like parts are connected to a circuits provided in the first and second units respectively.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.